class_docstr: Base class for encoder neural module to be used in NLP models. 
code: def output_types(self) -> Optional[Dict[str, NeuralType]]:
      return {
          "last_hidden_states": NeuralType(
              ("B", "T", "D"), ChannelType()
          )
      }
  
file_path: NeMo/nemo/collections/nlp/modules/common/encoder_module.py
imports: from abc import ABC
  from typing import Dict, Optional
  from nemo.core.classes import NeuralModule
  from nemo.core.neural_types import ChannelType, MaskType, NeuralType
label_desc: Use image node_id 2 for calling the EncoderModule obj's underlying member method code with example usage: obj.output_types() and returns: dict